fix(opengl): use Lazarus OpenGLContext

Replace OpenGLContextEx with OpenGLContext in MainForm, SpectrumViewOpengl, WaterfallViewOpengl, and WidebandView.

Switch the Lazarus project/program dependencies from LazOpenGLContextEx to LazOpenGLContext in ewsdr.lpi and ewsdr.lpr.

PixelScale was introduced in 092a202; restore the previous viewport/texture path: glViewport(0, 0, W, H), EnsureTexture(W, H), and UploadCurrentRow(W).

SpectrumViewOpengl.pas

@@ -16,7 +16,7 @@ interface
 
 uses
   Classes, SysUtils, Graphics, Controls, Math, Types,
-  OpenGLContextEx, GL,
+  OpenGLContext, GL,
   AppTheme, SpectrumView, VfoOverlay, BandPlanOverlay,
   WaterfallView, WaterfallViewOpengl;
 
@@ -980,9 +980,7 @@ begin
   H := FGLControl.Height;
   if (W <= 0) or (H <= 0) then Exit;
 
-  // HiDPI: viewport в физических пикселях FBO, координаты — логические
-  glViewport(0, 0, Round(W * FGLControl.PixelScale),
-             Round(H * FGLControl.PixelScale));
+  glViewport(0, 0, W, H);
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity;
   glOrtho(0, W, H, 0, -1, 1);